Oil contamination generally occurs when oil is released in to the environment from different sources such as natural seeps, extraction and transportation of petroleum including leaking vessels, drilling rigs, offshore oil platforms, and consumption of petroleum. The estimated amount of oil released to environment from various spills is 700,000 tons per year worldwide. In the Gulf of Mexico alone, the estimated average rate of seepage is 140,000 per year. Most frequent oil spills are small spills. However, some oil spills are much larger such as BP Deepwater Horizon oil spill (April 2010) that produced estimated total discharge of 670000 tons within a span of 3 months. Since oil spills and other related contamination can have catastrophic environmental consequences and current removal methods are limited, an improved removal of oil is urgently required. Traditional mechanical removal methods such as booms, skimmers, and suctions pumps have low removal efficiency and are effective only for thick oil slicks during the initial stage of oil spill. For low concentration of oil as present in the sheens of thickness <50 μm, various sorbent materials such as membranes, chemical dispersants, and polymer based foam absorbents are used for oil water separation. Although widely applied, these techniques are often impractical due to the limitations such as high operational cost and time, low adsorption efficiency, and environmental constraints.
Nanotechnology has gained significant research interest in the field of oil remediation in recent years and hydrophobic nanomaterials including hydrogels, nanotube sponges, nanowires, and nanoparticles have been widely studied. Despite showing good oil removal efficiency, these hydrophobic nanomaterials also have limitations in their practical applicability for oil-water separation in the depth of oil slicks. Moreover, many current methods use and produce hazardous materials using complex synthesis process with high energy and materials input. In our previous work, we developed a facile, and cheap synthesis technique to produce water soluble PVP-coated iron oxide NPs and applied these NPs for 100% oil removal at laboratory scale, as discussed in U.S. Publication 2015/0298993 of Jamie Lead published Oct. 22, 2014, which is incorporated by reference herein. However, successful transfer from lab- to industrial scale is essential for bringing a product to the market and to use them in large scale in-situ oil remediation. To illustrate this, to remove oil from the spill as big as BP Deepwater Horizon, this current method requires <106 Kg of the nanomaterials, assuming that each NP can sorb 30 times its mass.
Thus, an improved method for forming such nanoparticles is desired in the art, particularly for large mass quantities (>Kg).